Glenfiddich was the first distillery to consistently market 'single malt whisky' to an international audience in the early 1960s. They also produced the first single malt to be sold in an airport travel retail shop in 1963 and were the first distillery to open a visitor centre in 1969.
Single malt whisky is one of the most popular spirits in the world and people enjoy drinking it in every country on the planet. The term 'single malt' refers to a whisky which is distilled at one distillery and then matured and bottled. the alternative is a blended whisky, which is made up of whiskies that have been produced at different distilleries and normally of different ages. There is no such thing as a 'double malt'.
Single malts are made using barley which is then malted, a process where germination is started so as to turn the starch present in to natural sugars. These sugars are then turned to alcohol during the fermentation process. For more information on this see How is whisky made.
Single malt whiskies are produced in various locations around the world, but the most popular and well known are made in Scotland, Ireland and Japan. Single malt whisky can only be called 'scotch' if it comes from Scotland.